Sunlight Creek Stream Restoration | Park County, WY
CLIENT: Wyoming Game & Fish Department
PROJECT TYPE: River Restoration, Fish Passage Design, Fish Habitat Improvement
PROJECT LOCATION: Park County, Wyoming
WaterVation was hired by the Wyoming Game & Fish Department to develop stream restoration design plans for approximately one mile of Sunlight Creek in the Sunlight Wildlife Habitat Management Area. This area has been plagued by extreme lateral channel migration over the past 40 years which has been caused by changes in land use practices and exacerbated by subsurface irrigation return flows. The four actively eroding high-terrace banks are delivering over 1,700 tons of sediment per year and some have migrated over 100 feet laterally in one year. Brook trout habitat has been significantly reduced because of ongoing aggradation which has eliminated bedform diversity and clogged spawning gravels. WaterVation managed a multi-disciplinary design to develop stream restoration plans that were founded on natural channel design principals to address the main project goals of mitigating extreme high terrace bank erosion and restoring in-stream trout habitat for this red-ribbon fishery. Detailed stream assessments were performed to collect geomorphic, ecologic, and biologic data for both the project reach and a reference reach just upstream of the project area. The reference reach data was used to design aquatic habitat, the revegetation plan, and used as a starting point to design the proposed channel dimension, pattern, and profile. The proposed geomorphic channel design consisted of a major stream realignment and incorporated a low-flow channel, bankfull channel, and geomorphic floodplain that worked in unison to effectively convey sediment through the system. The proposed geomorphic channel design was validated with sediment transport modeling and 2-dimensional hydraulic modeling. Both 1-dimensional and 2-dimensional hydraulic models were used to design structural elements, evaluate shear stress and stream power for a range of flood events, and ensure that there was a suitable fish migration path through each riffle at various flood stages. Toe wood and log vane structures were incorporated into the stream restoration design to provide additional channel bank stability; incorporate planform and bedform diversity; enhance aquatic and terrestrial habitat; and comply with Section 404 permitting requirements. One oxbow pond was designed with a habitat connectivity channel to allow for fish refuge and rearing and five wetland depressions were incorporated into the floodplain.
